I love my little NC10, especially in my garden office. Sensibly, after inactivity (roughly equating to not touching a key for a while) it auto dims the screen brightness to only just visible. Normally, I can get the brightness back on by flicking the mouse or pressing the ctrl key. Sometimes, though, it dims and then the keys no longer work to un-dim it.
I finally tracked down a solution which doesn’t involve rebooting.
There are some Samsung customisations to the Windows Mobility Center (use Windows + X to open  it), one of which is the auto dimming on off switch (see the picture below). I turn it off and then on again and the screen pops back into life.
NB I think at one stage that Easy Display Manager crashed (it runs the on-screen brightness indication, I believe) so it can sometimes be helpful to check it is running / relaunch it.